From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Specification table outlining the ideal requirements for valve gear and combustion chamber design.
| Identifier | ExFiles\Box 134\2\ scan0043 | |
| Date | 18th July 1935 | |
| -2- HE/Rm.{William Robotham - Chief Engineer}15/KW.18.7.35. REQUIREMENT. | SPECIFICATION OF THE IDEAL. ---|--- Silence. | The valve gear should permit of valve silence being obtained at all times without the necessity of complicated hydraulic tappet adjustment. Durability. | The valve gear should impose the minimum load on the camshaft and followers. It should not necessitate a camshaft with high accelerations. Hydraulic tappet adjustment that may go wrong should be avoided. Efficiency. | Maximum breathing capacity, freedom from detonation, smoothness of operation, good slow running characteristics, facility for two spark plugs. The valve gear and combustion chamber must not necessitate a long or bulky engine. Accessibility. | The plugs should be easily accessible. Tappet adjustment should be simple, decarbonising reasonably easy. Economy in Production. | The valve gear should have the minimum number of parts, which should be simple to machine and fit. The combustion chamber should be easy to machine, and accessible. | ||